Airway management remains one of the most basic and important aspects of Emergency Medicine. The concepts and techniques described in this chapter can be applied in a variety of environments. Understanding the following concepts and having an opportunity to practice them will allow the provision of the most fundamental of all medical care, support of a patient’s airway.
The primary purpose of airway management is to facilitate the transport of oxygen to the lungs. Without oxygen, the brain begins to die within minutes.1 The secondary purpose of airway management is to protect the airway from aspiration or contamination with blood, fluids, or food. Airway management can be as simple as lifting a snoring patient’s chin or as involved as awake, fiberoptic-guided endotracheal intubation.
The fundamental importance of airway management is reflected by the fact that much of Basic Life Support taught by the American Heart Association is concerned with this vital function.2 The mission of airway management is “to ensure a patent airway, provide supplemental oxygen, and institute positive-pressure ventilation when spontaneous breathing is inadequate or absent.”3 These three key aspects of airway management warrant repeating. Ensure a patent airway. Provide supplemental oxygen. Provide positive-pressure ventilation.
Time is always critical when a patient needs airway support. The body’s limited oxygen stores are rapidly exhausted once breathing stops. A healthy individual having maximally breathed 100% oxygen will begin to become hypoxic and have brain injury after 5 minutes of apnea. A sick patient breathing room air will become hypoxic almost immediately upon becoming apneic.1
Oxygenation and ventilation remain the essential goals of airway management. Inadequate ventilation may occur for a variety of reasons. Spontaneously breathing patients may develop an airway obstruction due to blood, food, secretions, or tissue obstruction from the loss of normal pharyngeal tone. The conscious patient with an airway obstruction will be in obvious distress and is more likely to have an obstruction due to a foreign body, laryngeal edema, laryngospasm, tissue swelling from an infection, or a tumor. The unconscious patient is at risk for aspiration of gastric contents despite spontaneous respirations. Secure the airway of an unconscious patient with intubation (Chapter 18) and mechanical ventilation (Chapter 36).
ANATOMY AND PATHOPHYSIOLOGY
The upper airway includes the nasal, oral, pharyngeal, and laryngeal anatomy and physiology. This highly complex system is responsible for conveying warmed and filtered air to the trachea and lungs while simultaneously allowing for passage of liquids and solids to the esophagus. Phonation is a secondary physiologic function of the larynx.4 This highly sophisticated system allows us to drink liquid, eat food, breathe, and talk simultaneously. A profound system of reflexes is activated to protect the airway integrity if a small drop of liquid or a particle of food enters.5